Broad multiwavelength second-harmonic generation from two-dimensional /spl chi//sup (2)/ nonlinear photonic crystals of tetragonal lattice structure

2004 IEEE Journal of Selected Topics in Quantum Electronics  
We investigate the effects of lattice spacing and domain-filling ratio on the wavelength dependence in second-harmonic generation (SHG) from two-dimensional (2) nonlinear photonic crystals (2-D NPC) on lithium niobate. Spectral coverage of 150 and 200 nm around 1.5 and 1.9 m in quasi-phase-matched (QPM) SHG is obtained by angular rotation of the NPC with a lattice periodicity of 20 20 and 29.5 29.5 m 2 , respectively. The SHG signals are shown to have off-axial propagation directions determined
more » ... rections determined by the incident wavelength and the QPM vector. The intensity of the high-order reciprocal-lattice-vector (G mn )-assisted SHG signal is shown to depend on the domain-filling ratio. These observations are attributed to the unique dispersion of G mn together with the nonzero (2) (G mn ) nonlinearity in the 2-D QPM-NPC having a tetragonal lattice structure.
doi:10.1109/jstqe.2004.836001 fatcat:yrxgkmyvubgyde37z2mxdwjf3e